Scientists mine ‘star scar’ in France
Rochechouart was built on top of land hit by a meteorite 200 million years ago
Since early September, the denizens of this normally hushed burg in central France have been serenaded by an industrial drill poking holes around town and pulling up cylinders of rock.
That’s because Rochechouart, population 3,800, and its medieval castle are built on top of an astrobleme.
“An astrobleme — which literally means ‘star scar’ — is the name given to traces left by a major meteorite impact,” explained Philippe Lambert, one of the astrogeologists trying to unlock its secrets.
This particular impact crater was made by a massive space rock that crash-landed more than 200 million years ago, and has intrigued scientists since its discovery in the 19th century.
“You have a nugget under your feet!,” the famous Canadian astrophysicist Hubert Reeves enthused in 2011 while visiting the research project here he helped launch. Mr. Lambert directs the International Centre for Research on Impacts at Rochechouart (CIRRI).
The centre is coordinating the first-ever drilling and excavation at the site.
The impact — which vaporised the meteorite — was roughly equivalent to several thousand Hiroshima-sized atomic bombs, and almost certainly destroyed all life within a radius of some 200 kilometres. The landscape was changed forever.
The drilling, scheduled through November, will yield 20 core samples.
The €600,000 project, funded by the French government and the European Union, could be the beginning of a long adventure, said Mr. Lambert. “There’s everything here to justify an open-air laboratory,” he mused.
Some scientists hope to tease out remaining mysteries about how such meteorites form, and what that might tell us about their evolution in space.
Others are on the hunt for chemical traces that could shed light on the emergence of life on Earth, and which of the raw ingredients essential for life came from space.
Geologists are curious about how such a cataclysmic impact might have released water held within rock formations, while palaeobiologists are looking at how an event that could destroy life, at the same time, creates conditions for new lifeforms to emerge.